Showerhead assembly with multiple fluid delivery zones

ABSTRACT

The present disclosure relates to a semiconductor processing apparatus. The processing chamber includes a chamber body and lid defining an interior volume, a substrate support disposed in the interior volume and a showerhead assembly disposed between the lid and the substrate support. The showerhead assembly includes a faceplate configured to deliver a process gas to a processing region defined between the showerhead assembly and the substrate support and a underplate positioned above the faceplate, defining a first plenum between the lid and the underplate, the having multiple zones, wherein each zone has a plurality of openings that are configured to pass an amount of inert gas from the first plenum into a second plenum defined between the faceplate and the underplate, in fluid communication with the plurality of openings of each zone such that the inert gas mixes with the process gas before exiting the showerhead assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional Application Ser.No. 62/239,547, filed Oct. 9, 2015, which is hereby incorporated byreference in its entirety.

BACKGROUND

Field

Embodiments of the present disclosure generally relate to a showerheadassembly for a semiconductor processing apparatus, and more particularlyto a showerhead assembly having multiple zones for independent controlof fluid passing through the showerhead assembly.

Description of the Related Art

Reliably producing sub-half micron and smaller features is one of thekey technology challenges for next generation very large scaleintegration (VLSI) and ultra large scale integration (ULSI) ofsemiconductor devices. However, as the limits of circuit technology arepushed, the shrinking dimensions of VLSI and ULSI technology have placedadditional demands on processing capabilities. Reliable formation ofgate structures on the substrate is helpful to VLSI and ULSI success andto the continued effort to increase circuit density.

As circuit densities increase for next generation devices, the widths ofinterconnects, such as vias, trenches, contacts, gate structures andother features, as well as the dielectric materials therebetween,decrease to 45 nm and 32 nm dimensions and beyond. In order to enablethe fabrication of next generation devices and structures, threedimensional (3D) stacking of features in semiconductor chips is oftenutilized. In particular, fin field effect transistors (FinFETs) areoften utilized to form three dimensional (3D) structures insemiconductor chips. By arranging transistors in three dimensionsinstead of conventional two dimensions, multiple transistors may beplaced in the integrated circuits (ICs) very close to each other. Ascircuit densities and stacking increase, the ability to selectivelydeposit subsequent materials on previously deposited materials gainsimportance. The ability to control fluids delivered to substratesthrough showerhead assemblies has become increasingly helpful in aidingthe successful fabrication of next generation devices.

Thus, there is a need for an improved showerhead assembly.

SUMMARY

In one embodiment, a showerhead assembly is disclosed herein. Theshowerhead assembly includes a faceplate and a underplate. The faceplatehas a first side and a second side. The faceplate has a plurality ofapertures configured to deliver a process gas from the first side to thesecond side. The underplate is positioned adjacent the first side of thefaceplate. The underplate has multiple zones, wherein each zone has aplurality of apertures that are configured to pass inert gas through theunderplate into a plenum defined between the faceplate and theunderplate. The inert gas mixes with a process gas in the plenum.

In another embodiment, a showerhead assembly is disclosed herein. Theshowerhead assembly includes a faceplate and a underplate. Theshowerhead includes a first side and a second side. The faceplate has aplurality of apertures configured to deliver a process gas from thefirst side to the second side. The underplate is positioned adjacent thefirst side of the faceplate defining a plenum between the faceplate andthe underplate, wherein the underplate has multiple zones. Each zoneincludes a conductance controller assembly extending from the underplateinto the plenum. The conductance controller assembly is configured tocontrol the conductance of process gas within the plenum.

In another embodiment, a showerhead assembly is disclosed herein. Theshowerhead assembly includes a faceplate and a underplate. Theshowerhead includes a first side and a second side. The faceplate has aplurality of apertures configured to deliver a process gas from thefirst side to the second side. The underplate is positioned adjacent thefirst side of the faceplate defining a plenum between the faceplate andthe underplate, wherein a plurality of gas lines are formed through theunderplate opening into the plenum. The plurality of gas lines formmultiple zones in the underplate, wherein each zone is configured toprovide a different amount of process gas to the plenum.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 illustrates a processing chamber having a showerhead assembly,according to one embodiment.

FIG. 2 illustrates a gas delivery system of FIG. 1, according to oneembodiment.

FIG. 3 illustrates a processing chamber having a showerhead assembly,according to one embodiment.

FIG. 4 illustrates a processing chamber having a showerhead assembly,according to one embodiment.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements and features of oneembodiment may be beneficially incorporated in other embodiments withoutfurther recitation.

It is to be noted, however, that the appended drawings illustrate onlyexemplary embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

DETAILED DESCRIPTION

FIG. 1 illustrates a chemical vapor deposition (CVD) processing chamber100 having a showerhead assembly 112, according to one embodiment. Theprocessing chamber 100 includes a chamber body 102 having sidewalls 104,a bottom 105, and a lid 106. The sidewalls 104 and lid 106 define aninterior volume 108. A substrate transfer port 110 may be formed in thesidewall 104 for transferring substrates into and out of the interiorvolume 108.

A substrate support assembly 126 is disposed within the interior volume108 of the processing chamber 100 below the showerhead assembly 112. Thesubstrate support assembly 126 is configured to support a substrate 101during processing. The substrate support assembly 126 may include aplurality of lift pins 128 movably disposed therethrough. The lift pins128 may be actuated to project from a support surface 130 of thesubstrate support assembly 126, thereby placing the substrate 101 in aspaced-apart relation to the substrate support assembly 126 tofacilitate transfer with a transfer robot (not shown) through thesubstrate transfer port 110.

The showerhead assembly 112 is disposed in the interior volume 108 andis coupled to the lid 106. The showerhead assembly 112 includes aunderplate 114 and a faceplate 118. The underplate 114 is positionedbelow the lid 106 such that a first plenum 120 is formed between theunderplate 114 and the lid 106. In one embodiment, the showerheadassembly 112 further includes a diffuser plate 116 positioned betweenthe underplate 114 and the faceplate 118. The diffuser plate 116 forms asecond plenum 124 between the underplate 114 and the diffuser plate 116and a third plenum 122 between the diffuser plate 116 and the faceplate118.

The first plenum 120 is partitioned into a plurality of zones by theunderplate 114. For example, in the embodiment shown in FIG. 1, thefirst plenum 120 is partitioned into zone Z2 and zone Z3. The firstplenum 120 is configured to receive an inert gas from a gas deliverysystem 180 coupled to an inert gas source 144. The inert gas may beprovided to each zone Z2 and Z3. For example, a greater amount of inertgas may be provided to Z2 compared to that of Z3. In one embodiment, thegas delivery system 180 uses a flow ratio control technique to controlthe amount of inert gas delivered to zone Z2 relative to zone Z3. In oneembodiment, different combinations of pneumatic valves and sizedorifices may be used to achieve gas splitting. In another embodiment,using different gas delivery valves, such as piezo and ALD valves, whenused in combination can achieve the same gas splitting results to thedifferent zones.

The underplate 114 is configured to provide the inert gas from the firstplenum 120 to the second plenum 124. The underplate 114 includes aplurality of apertures 132. The apertures 132 allow for fluidcommunication between the first plenum 120 and the second plenum 124.The plurality of apertures 132 are positioned beneath the zones Z2 andZ3, and thus, the apertures 132 are grouped into corresponding zones Z2,Z3 in the underplate 114.

The processing chamber 100 further includes a central conduit 138. Thecentral conduit 138 is formed through the lid 106 and opens into thesecond plenum 124. The central conduit 138 is configured to provide aprocess gas to the second plenum 124 from the process gas source 140. Inthe second plenum 124, the process gas supplied by the central conduit138 mixes with the inert gas provided from the underplate 114. Becausethe amount of inert gas entering the second plenum 124 through each zoneof the underplate 114 is different, the ratio of process gas to inertgas is not uniform across the second plenum 124. Thus, in the secondplenum 124 there are three zones (A1, A2, A3) of process gas dilution bythe inert gas. A first zone, A1, directly beneath the central conduit138 in which the process gas is not diluted by the first gas; the secondzone A2 beneath Z2 in the first plenum 120; and the third zone A3beneath Z3 in the first plenum 120. Each zone A1-A3 may include adifferent ratio of inert gas to the process gas. Creating multiple zonesof process gas in the plenum 120 allows for a gradient in thedistribution of the process gas exiting the faceplate and delivered tothe substrate to improve film deposition properties.

The diffuser plate 116 includes a plurality of apertures 134. Theplurality of apertures 134 allows for fluid communication between thesecond plenum 124 and the third plenum 122. The diffuser plate 116 isconfigured to disperse the gas mixture provided to the third plenum 122.The third plenum 122 is in fluid communication with a processing region142 defined between the faceplate 118 and the substrate support assembly126 through a plurality of apertures 136 formed through the faceplate118. The apertures allow for fluid communication between the thirdplenum 122 and the processing region 142.

A controller 190 is coupled to the processing chamber 100. Thecontroller 190 includes a central processing unit (CPU) 192, a memory194, and support circuits 196. The controller 190 is utilized to controlthe amount of inert gas supplied to each zone Z2, Z3 of the first plenum120. Controlling the amount of inert gas to each zone allows for gasdistribution uniformity exiting the showerhead assembly 112 to becontrolled. The CPU 192 may be of any form of a general purpose computerprocessor that can be used in an industrial setting. The softwareroutines can be stored in the memory 194, such as random access memory,read only memory, floppy or hard disk drive, or other form of digitalstorage. The support circuits 196 are conventionally coupled to the CPU192 and may comprise cache, clock circuits, input/output subsystems,power supplies, and the like. The software routines, when executed bythe CPU 192, transform the CPU 192 into a specific purpose computer(controller) 190 that controls the processing chamber 100 such that theprocesses are performed in accordance with the present disclosure. Thesoftware routines may also be stored and/or executed by a secondcontroller (not shown) that is located remotely from the chamber.

FIG. 2 illustrates the gas delivery system 180 according to oneembodiment. The gas delivery system 180 includes a flow ratio controldevice 200 coupled to each zone Z2, Z3 of the first plenum 120. The flowratio control device 200 includes a supply line 202 coupled to the gassource 144, a plurality of valves 204 a, 204 b, a plurality of orifices206 a, 206 b, and an outlet line 208. The supply line 202 delivers aninert gas to each valve 204 a-204 b. The valves 204 a-204 b areindependently controlled, and are configured to open and close tocontrol the amount of inert gas supplied to each respective orifice 206a-206 b. Each orifice 206 a-206 b may be sized differently, such thateach zone may receive a different amount of gas flow. Additional valvesand orifices may be added or subtracted based on the number of zonesdesired in the first plenum 120.

FIG. 3 illustrates a CVD processing chamber 300, according to oneembodiment. The processing chamber 300 includes a chamber body 302having sidewalls 304, a bottom 305, and a lid 306. The sidewalls 304 andlid 306 define an interior volume 308. A substrate transfer port 310 maybe formed in the sidewall 304 for transferring substrates into and outof the interior volume 308.

The processing chamber 300 further includes a showerhead assembly 312.The showerhead assembly 312 includes a underplate 314 and the faceplate118. The underplate 314 is positioned below the lid 306 such that afirst plenum 320 is formed between the underplate 314 and the lid 306.In one embodiment, the showerhead assembly 312 further includes thediffuser plate 116 positioned between the underplate 314 and thefaceplate 118. The diffuser plate 116 forms a second plenum 324 betweenthe underplate 314 and the diffuser plate 116 and a third plenum 322between the diffuser plate 116 and the faceplate 118. The centralconduit 138 is formed through the lid 306 and opens into the secondplenum 324. The central conduit 138 is configured to provide a processgas to the second plenum 324 from the process gas source 140. An inertgas line 380 is formed through the lid 306 and underplate 314 and opensinto the second plenum 324. The inert gas line 380 is configured toprovide an inert gas to the second plenum 324 from the inert gas source382, such that the inert gas mixes with the process gas in the secondplenum 324.

A movable conductance controller assembly 348 is disposed in the firstplenum 320 and extends through the underplate 314 into the second plenum324. The movable conductance controller assembly 348 is configured tocontrol the conductance through a gap defined between the diffuser plate116 and the underplate 314 to control the amount of gas flowing throughdifferent regions (zones) of the second plenum 324. The movableconductance controller assembly 348 includes a conductance controller350 and an actuator 352. In one embodiment, the conductance controller350 may include a shaft 354 and a plate 356. The shaft 354 may extendthrough the underplate 314 into the second plenum 324 such that theplate 356 is within the second plenum 324. In one embodiment, an o-ring358 and bellows 360 may be used to maintain isolation between the firstplenum 320 and the second plenum 324.

The actuator 352, such as a motor or cylinder, may be coupled to theconductance controller 350. In one embodiment, the motor may be mountedto a z-stage 362 disposed in the first plenum 320. The actuator 352 isconfigured to move the conductance controller 350 in the z-direction.Raising and lowering the conductance controller 350 controls the amountof flow of the process gas mixture to be distributed to the secondplenum 324. For example, a larger gap between the conductance controller350 and the diffuser plate 116 allows for a greater amount of processgas mixture within the second plenum 324. Conversely, a smaller gapbetween the conductance controller 350 and the diffuser plate 116 allowsfor a lesser amount of a process gas mixture within the second plenum324. Each conductance controller 350 disposed in the first plenum 320may be controlled independently to define a plurality of zones ofprocess gas mixture in the second plenum 324. The plurality of apertures134 are positioned beneath the plurality of zones. The apertures 134 aregrouped in corresponding zones in the diffuser plate 116. Because theconcentration of process gas mixture entering the third plenum 322through each zone in the diffuser plate 116 is different, theconcentration of process gas mixture is not uniform across the thirdplenum 322. Multiple zones of process gas mixture are defined in thethird plenum 322, allowing for a gradient in the distribution of theprocess gas mixture exiting the faceplate 118 and delivered to thesubstrate to improve film deposition properties.

A controller 390 is coupled to the processing chamber 300. Thecontroller 390 includes a central processing unit (CPU) 392, a memory394, and support circuits 396. The controller 390 may be coupled to theactuator 352 to control the conductance controller 350. Controlling theconductance controller 350 allows for a gradient in the distribution ofthe process gas in the showerhead assembly 312. The CPU 392 may be ofany form of a general purpose computer processor that can be used in anindustrial setting. The software routines can be stored in the memory394, such as random access memory, read only memory, floppy or hard diskdrive, or other form of digital storage. The support circuits 396 areconventionally coupled to the CPU 392 and may comprise cache, clockcircuits, input/output subsystems, power supplies, and the like. Thesoftware routines, when executed by the CPU 392, transform the CPU 392into a specific purpose computer (controller) 390 that controls theprocessing chamber 300 such that the processes are performed inaccordance with the present disclosure. The software routines may alsobe stored and/or executed by a second controller (not shown) that islocated remotely from the chamber.

FIG. 4 illustrates a CVD processing chamber 400 according to yet anotherembodiment. The processing chamber 400 includes a chamber body 402having sidewalls 404, a bottom 405, and a lid 406. The sidewalls 404 andlid 406 define an interior volume 408. A substrate transfer port 410 maybe formed in the sidewall 404 for transferring substrates into and outof the interior volume 408.

The processing chamber 400 further includes a showerhead assembly 412.The showerhead assembly 412 includes a underplate 414 and the faceplate118. The underplate 414 is positioned below the lid 406 such that aplenum 420 is formed between the underplate 414 and the faceplate 118. Aplurality of gas lines 424 coupled to a gas source 440 extend throughthe lid 406 and underplate 414 to provide process gas to the plenum 420.Each line 424 may be configured to deliver a different concentration ofprocess gas to the plenum 420. For example, multiple zones of processgas may be formed in the plenum 420 by diluting the concentration ofprocess gas with an inert gas in the outer gas lines 424 compared to theconcentration of the process gas flowing through the inner gas lines424. The plurality of apertures 136 are positioned beneath the zones,and thus the apertures 136 are grouped into corresponding zones.Creating multiple zones of process gas concentration in the plenum 420allows for a gradient in the amount of process gas delivered to thesubstrate to improve film deposition properties.

A controller 490 is coupled to the processing chamber 400. Thecontroller 490 includes a central processing unit (CPU) 492, a memory494, and support circuits 496. The controller 490 may be coupled to thegas source 440 to control the concentration of process gas supplied toeach gas line 424. Controlling each respective gas line 424 allows formodulation of the gas distribution in the showerhead assembly. The CPU492 may be of any form of a general purpose computer processor that canbe used in an industrial setting. The software routines can be stored inthe memory 494, such as random access memory, read only memory, floppyor hard disk drive, or other form of digital storage. The supportcircuits 496 are conventionally coupled to the CPU 492 and may comprisecache, clock circuits, input/output subsystems, power supplies, and thelike. The software routines, when executed by the CPU 492, transform theCPU 492 into a specific purpose computer (controller) 490 that controlsthe processing chamber 400 such that the processes are performed inaccordance with the present disclosure. The software routines may alsobe stored and/or executed by a second controller (not shown) that islocated remotely from the chamber.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. A showerhead assembly, comprising: a faceplatehaving a first side and a second side, the faceplate having a pluralityof apertures configured to deliver a process gas from the first side tothe second side; and a underplate positioned adjacent the first side ofthe faceplate, the underplate having multiple zones, wherein each zonehas a plurality of apertures that are configured to pass inert gasthrough the underplate into a plenum defined between the faceplate andthe underplate, wherein the inert gas mixes with a process gas in theplenum.
 2. The showerhead assembly of claim 1, further comprising: adiffuser plate disposed between the faceplate and the underplate.
 3. Theshowerhead assembly of claim 1, wherein the plurality of apertures inthe underplate are grouped to the multiple zones.
 4. The showerheadassembly of claim 1, wherein the plurality of apertures in the faceplateare positioned beneath the plurality of zones of the underplate.
 5. Theshowerhead assembly of claim 1, wherein the inert gas is delivered tothe plenum by a plurality of gas lines, wherein each gas line comprises:a valve configured to open and close the gas line; and an orificeconfigured to control a flow rate of the inert gas through the gas line.6. The showerhead assembly of claim 1, wherein the plurality of zonesformed in the underplate corresponds to a plurality of zones in thefaceplate.
 7. The showerhead assembly of claim 1, wherein each zone isprovided with a different concentration of inert gas.
 8. A showerheadassembly, comprising: a faceplate having a first side and a second side,the faceplate having a plurality of apertures configured to deliver aprocess gas from the first side to the second side; and a underplatepositioned adjacent the first side of the faceplate defining a plenumbetween the faceplate and the underplate, wherein the underplate hasmultiple zones, wherein each zone includes a conductance controllerassembly extending from the underplate into the plenum, the conductancecontroller assembly configured to control the conductance of process gaswithin the plenum.
 9. The showerhead assembly of claim 8, furthercomprising: a diffuser plate disposed between the underplate and thefaceplate.
 10. The showerhead assembly of claim 8, wherein the pluralityof apertures in the faceplate correspond to the multiple zones in theunderplate.
 11. The showerhead assembly of claim 8, wherein the movableconductance controller assembly comprises: a conductance controller,comprising: a shaft; and a plate coupled to the end of the shaft; and amotor coupled to the conductance controller, the motor configured toraise or lower the conductance modulator.
 12. The showerhead assembly ofclaim 8, wherein the conductance controller controls the amount ofprocess gas exiting the faceplate.
 13. The showerhead assembly of claim12, wherein the conductance controller assembly further comprises: az-stage configured to support the motor.
 14. The showerhead assembly ofclaim 8, wherein each zone contains a different concentration of processgas.
 15. A showerhead assembly, comprising: a faceplate having a firstside and a second side, the faceplate having a plurality of aperturesconfigured to deliver a process gas from the first side to the secondside; and a underplate positioned adjacent the first side of thefaceplate defining a plenum between the faceplate and the underplate,wherein a plurality of gas lines are formed through the underplateopening into the plenum, the plurality of gas lines forming multiplezones in the underplate, wherein each zone is configured to provide adifferent amount of process gas to the plenum.
 16. The showerheadassembly of claim 15, further comprising: a diffuser plate disposedbetween the underplate and the faceplate.
 17. The showerhead assembly ofclaim 15, wherein each zone in the underplate corresponds to a zone inthe faceplate.
 18. The showerhead assembly of claim 15, wherein theplurality of apertures in the faceplate correspond to the multiple zonesin the underplate.
 19. The showerhead assembly of claim 15, wherein eachgas line delivers a different concentration of process gas.
 20. Theshowerhead assembly of claim 15, wherein the plurality of apertures inthe faceplate are positioned beneath each zone in the underplate.